He was terrible against United giving away a needless penalty and then almost doing it again later. That game seemed to show that he hasn't got rid of the rash challenges especially against the top players.
West Ham he didn't have to do anything since they didn't really try to score. That was kind of a perfect game for him since there was no need for him to think about what to do or get taken advantage of because of his lack of football IQ.
Sheffield again showed his terrible defensive awareness and he was often out of position leading to chances and goals.
The team looked a lot better with Toby and Sanchez paired together because Toby can do the heavy lifting for Sanchez allowing him to play a simpler game. Sanchez doesn't have to make as many decisions with or without the ball that he does when Dier is there putting him in tough positions.
I don't see how or why we would expect him to cut out the rash challenges when they arise from his poor defensive instincts that get him into bad spots so he reacts quickly which is terrible for him.
Maguire is fun to make fun of but there is not a chance that Dier looked better than him. Not really sure that he looked better than Lindelof or Baily either if we take off the homer glasses either.
Dier is flat out bad and if he were playing for another team, especially a rival, we would be laughing about them continuing to run him out there after giving away so many chances/goals for the other team.